Learn More About Static Electricity?
Table of Contents
When we rub two different materials together, which becomes positively charged and which becomes negative?
Scientists have ranked materials in order of their ability to hold or give up electrons. This ranking is called the triboelectric series.
(Learn how to
Eliminate Static Electricity
problems in your home or office.)
A list of some common materials is shown below. Under ideal conditions, if two materials are rubbed together, the one higher on the list should give up electrons and become positively charged.
Conservation of Charge
When we charge something with static electricity, no electrons are made or destroyed. No new protons appear or disappear. Electrons are just moved from one place to another. The net, or total, electric charge stays the same. This is called the principle of conservation of charge.
Charged objects create an invisible electric force field around themselves. The strength of this field depends on many things, including the amount of charge, distance involved, and shape of the objects. This can become very complicated. We can simplify things by working with "point sources" of charge. Point sources are charged objects which are much, much smaller than the distance between them.
Charles Coulomb first described electric field strengths in the 1780's. He found that for point charges, the electrical force varies directly with the product of the charges. In other words, the greater the charges, the stronger the field. And the field varies inversely with the square of the distance between the charges. This means that the greater the distance, the weaker the force becomes. This can be written as the formula:
F = k (Q1 X Q2) / d2
where F is the force, Q1 and Q2 are the charges, and d is the distance between the charges. K is the proportionality constant, and depends on the material separating the charges.
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Easy Reading - What is Static Electricity?
You walk across a rug and reach for a doorknob. ZAP!! You get a shock. Did you ever ask why? What is static electricity?
Everything we see is made up of tiny little parts called atoms. The atoms are made of even smaller parts. These are called protons, electrons and neutrons. They are very different from each other in many ways.
One way they are different is their "charge." Protons have a positive (+) charge. Electrons have a negative (-) charge. Neutrons have no charge.
Usually, atoms have the same number of electrons and protons. Then the atom has no charge, it is "neutral."
But if you rub things together, electrons can move from one atom to another. Some atoms get extra electrons. They have a negative charge. Other atoms lose electrons. They have a positive charge. When charges are separated like this, it is called static electricity.
If two things have the same charge, they repel, or push away from each other.
If two things have different charges, they attract, or pull towards each other.
So, why does your hair stand up after you take your hat off?
When you pull your hat off, it rubs against your hair. Electrons move from your hair to the hat.
Now each of the hairs has the same positive charge. Things with the same charge repel each other. So the hairs try to move away from each other. The farthest they can get is to stand up and away from all the other hairs.
If you walk across a carpet, electrons move from the rug to you. Now you have extra electrons. Touch a door knob and ZAP! The electrons move from you to the knob. You get a shock.
Easy Science Projects
Want to light a light bulb using a balloon? Bend a stream of water? Try these quick and easy science projects at home.....